I underwent a tubal reversal surgery in January after having my tubes tied 19 years ago. I am now 5 weeks pregnant. My hcg levels have been monitored over the past two weeks and have been rising accordingly (practically tripling each time) although an ultrasound has not been able to fully confirm a gestational sack. My last two hcg counts seem to indicate a slower rise (2734 to 3638) I'm worried this may not be a good sign... should I be?